The present disclosure relates to an electrophotographic photosensitive member, a process cartridge, and an image forming apparatus.
An electrophotographic image forming apparatus (for example, a printer or a multifunction peripheral) includes an electrophotographic photosensitive member as an image bearing member. The electrophotographic photosensitive member typically includes a conductive substrate and a photosensitive layer located either directly or indirectly on the conductive substrate. A photosensitive member such as described above that includes a photosensitive layer containing a charge generating material, a charge transport material (for example, a hole transport material), and a resin (organic material) for binding the aforementioned materials is referred to as an organic electrophotographic photosensitive member.
Among such organic electrophotographic photosensitive members, an organic electrophotographic photosensitive member that contains a charge transport material and a charge generating material in the same layer and implements functions of charge generation and charge transport through the same layer is referred to as a single-layer electrophotographic photosensitive member.
In recent years, progress has been made, not only in development of monochrome image forming apparatuses, but also in development of color image forming apparatuses. There has also been progress in providing smaller and faster image forming apparatuses. As a consequence of such progress, an electrophotographic photosensitive member is required to have high sensitivity in order to be compatible with a high-speed process. However, in a situation in which an electrophotographic photosensitive member is used while exposed to a gas of an oxidizing substance (for example, ozone) or a gas of a nitrogen oxide (for example, NOx) and particularly in a situation in which the electrophotographic photosensitive member is used repeatedly, a problem of reduced sensitivity of the electrophotographic photosensitive member tends to occur.
In one known example, an image forming apparatus includes an electrophotographic photosensitive member that contains at least a diarylamine compound in an outermost layer.
In another known example, an electrophotographic apparatus includes an electrophotographic photosensitive member that includes a photosensitive layer containing a triphenylamine charge mobilizer (charge transport material) and a charge generating material composed of oxytitanium phthalocyanine (titanyl phthalocyanine).